Comet, Not Asteroid, Killed Dinosaurs, Study Suggests

The rocky object that wiped out the dinosaurs 65 million years ago may have been a comet, rather than an asteroid, scientists say.

The 112-mile (180 kilometers) Chicxulub crater in Mexico was made by the impact that caused the extinction of dinosaurs and about 70 percent of all species on Earth, many scientists believe. A new study suggests the crater was probably blasted out by a faster, smaller object than previously thought, according to research presented this week at the 44th Lunar and Planetary Science Conference in The Woodlands, Texas.

Evidence of the space rock’s impact comes from a worldwide layer of sediments containing high levels of the element iridium, dubbed the Cretaceous-Paleogene (K-Pg) boundary, which could not have occurred on Earth naturally.